Abstract A process for making the axial adjustment of the deflection yoke on a color cathode ray tube display assembly of the shadow mask variety. Before this adjustment is attempted, the color purity adjustment must first be made. This involves disabling two of the three electron guns and then, by known manipulation of the ''''color purity magnets'''' causing the beam landings to coincide with the correct phosphor dots in the center of the tube. The deflection yoke is then adjusted while normal operating potentials are applied to the tube, except for the disabled guns, normal deflection signals are supplied to the yoke, and an axial magnetic field is applied at the tube faceplate. The axial field is made strong enough to shift non axial electron beams to the adjacent phosphor dots thereby creating a color display pattern having radial components of a color corresponding to that of one or more of the two disabled electron guns. When the deflection yoke is correctly positioned, the radial pattern components will be symmetrical and will have straight lines. Incorrect adjustment will result in skewed or curved components. The yoke is moved to achieve a pattern having the highest degree of symmetry and straight edges.
A process for making the deflection yoke axial adjustment on an operating color cathode ray tube display assembly of the shadowmask variety, said process comprising the steps of: a. locating the geometrical center of the display of said tube, b. disabling two of the three electron guns in said tube, c. applying a magnetic field along the center axis of said tube to produce a color display having a propeller shape, d. adjusting the purity magnets of said assembly to center the hub of said propeller shape on said center of said display, and e. adjusting said deflection yoke axially on said tube to produce a propeller pattern having blades of maximum straightness and symmetry.
Claim 2
Dependent Claim
115 words
A process for making the deflection yoke axial adjustment on an operating color cathode ray tube display assembly of the shadowmask variety, said process comprising the steps of: a. locating the geometrical center of the display of said tube, b. disabling two of the three electron guns in said tube, c. applying a magnetic field along the center axis of said tube to produce a color display having a propeller shape, d. adjusting the purity magnets of said assembly to center the hub of said propeller shape on said center of said display, and e. adjusting said deflection yoke axially on said tube to produce a propeller pattern having blades of maximum straightness and symmetry.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein an additional step comprises degaussing said tube.
Claim 4
Dependent Claim
43 words
The process of claim 1 wherein said magnetic field is produced by a permanent magnet located adjacent the center of the face of said cathode ray tube, and said propeller shape is produced by controlling the proximity of said magnet to said face.
Claim 5
Dependent Claim
42 words
The process of claim 1 wherein said magnetic field is produced by passing a direct current through a coil located adjacent the face of said cathode ray tube, and said propeller shape is produced by controlling the current passing through said coil.
Claim 6
Dependent Claim
23 words
The process of claim 4 wherein alternating current is passed through said coil to degauss said tube after making said deflection yoke adjustment.